Effects of Type I Migration on Terrestrial Planet Formation
Bibliographic record
Abstract
Planetary embryos embedded in a gas disk suffer a decay in semimajor axis—type I migration—due to the asymmetric torques produced by the interior and exterior wakes raised by the body. This presents a challenge for standard oligarchic approaches to forming the terrestrial planets, as the timescale to grow the progenitor objects near 1 AU is longer than that for them to decay into the Sun. In this paper we investigate the middle and late stages of oligarchic growth using both semianalytic methods (based on Thommes and coworkers) and N -body integrations and vary gas properties such as dissipation timescale in different models of the protoplanetary disk. We conclude that even for near-nominal migration efficiencies and gas dissipation timescales of ∼1 Myr, it is possible to maintain sufficient mass in the terrestrial region to form Earth and Venus if the disk mass is enhanced by factors of ∼2–4 over the minimum-mass model. The resulting configurations differ in several ways from the initial conditions used in previous simulations of the final stages of terrestrial accretion, chiefly in (1) larger interembryo spacings, (2) larger embryo masses, and (3) up to ∼0.4 M ⊕ of material left in the form of planetesimals when the gas vanishes. The systems we produce are reasonably stable for ∼100 Myr and therefore require an external source to stir up the embryos sufficiently to produce final systems resembling the terrestrial planets.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".